Is Zakat now obligatory upon a man who owns 20 mature sheep upon which a Ḥawl (full year) has passed, and 20 young sheep upon which a Ḥawl has not passed?

If the sheep are foddered (fed), there is no zakat on them according to the majority of scholars. If they are pasturing (sāʾimah), then they have conditions that have been detailed previously. The nisab (minimum taxable amount) for sheep is forty ewes. There is no zakat on your sheep if their young are not offspring of the adults. However, if the young are offspring of the adults, then zakat is obligatory on them according to some scholars, due to the nisab being complete, and what is due is one ewe.